Governments allocate substantial resources to regulate the environmental consequences of industrial activity. However, little is known about the economic value associated with such oversight. We document a 1.1% increase in US housing values following the establishment of a nearby monitoring station. This positive price effect is attributable to improvements in air quality as we demonstrate a 46.7% reduction in toxic emissions and a 2.6% decrease in the number of industrial facilities in the area subject to additional monitoring. Conservative estimates suggest that the value of new monitoring stations exceeds $52 billion.
